A developmental comparison of modes of perceptual adaptation to an altered visual-proprioceptive task

Following from a developmental hypothesis it was predicted that schizophrenics and normal children would adapt in a similar mode to an altered visual-proprioceptive task. Nine good premorbid schizophrenics, nine poor premorbid schizophrenics, nine normal children, and nine normal adults were tested for adaptation to a brief visual displacement of their hand images. The procedure involved the marking of a target design prior to and after exposure to a 20 diopter prism. The distance between preexposure and postexposure markings was measured for each subject. The schizophrenics and normal children showed significantly less compensatory, or adaptive, shift in their performances following the visual-displacenent procedure. There was no relationship found between adaptive shift and I. Q. as measured by the Peabody Picture Vocabulary Test. The results lend support for the regression hypothesis for schizophrenics in terms of perceptual functioning.